Railway traffic controlling apparatus



June 2. 1931. R. A. MQCANN v l RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Nov. 28, 1928 Patented `lune 2, 193i UNITED S'E'All'l QFFICE 'l RONAllfDA A. MCGAlTN, OF SWISSVAL'E, PENNSYLVANIA, ASSIGNOR TO THE UNION SV/*ITCEI 8a SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA,A CORPORATION' OF PENNSYLVANIA RAILWAY TRAFFIC CONTEOLLENG APPARATUS Application filed November 28, 1928, Serial No. 322,421.

My invention relates to railway trailic controlling apparatus, and particularly to apparatus ot' the type comprising train carried governing means controlled by energy received from the trackway.

The apparatus cove-red by the present application is an improvement on the apparatus disclosed and claimed in a co-pending application by Lloyd V. Lewis tiled on August Q, 1927, Serial No. 210165, for railway traiiic controlling apparatus.

I will describe one form ot apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view illustrating one torni et appara.- tus embodying my invention.

Referring to the drawing, the reference characters' l and la designate the track rails oi a stretch ot railway track over which tratlic moves in t-he direction indicated by the arrow. These rails are divided, by means oi' insulated joints 2, into a plurality of successive track sections, of which only one secing. Train controlling current is supplied to the. rails ot this section from a suitable iii) source ot energy such as an alternator M. The current supplied to the trackway by this alternator may be of a frequency ot the order of the usual commercial alternating current, such for example, as 60 cycles or 100 cycles per second, Y

The supply of current to the track rails is controlled by a code transmitting device comprising a plurality of rotatable cams each designated by the reference character O with a suitable distinguishing exponent. The cams O are driven at a constant speed by a suitable motor .l which is supplied with current from the alternator M. n The cam O1 is provided with a plurality ot swells 5 spaced aboutits periphery, which swells successively ope-rate a Contact 6 to periodically close the contact as the cam O1 is rotated. ln similar manner the cams O2 and 03 are provided with diiierent numbers of swells 5 which control contacts 7 and 8, respectively. One terminal' of the alternator M is constantly connected with rail l of section A-B,

Renewed November 6, 1930.

and the other terminal ofthe alternator is connected with the rail la through a current limiting impedance Z, and one 'ofv the contacts 6, 7,- or 8, depending upon traliic conditions, v l

lt isma-nitest that the alternating current supplied to the rails ofthe trackway by alternator M is periodically varied at thetrequency of operation of the contact of the code transmitting device interposed between the alternator and the track rail la. The code transmitting device may be constructed to cause such variations at any reasonable frequencies, but tor purposes of illustration, l will assume that the cams O are rotating .at revolutions per minute, that cam .O1 has 4: swells, that cam O2 has 6 swells, and that cam 03 has nine swells.` The selection between'the several contacts of the coding device in accordance with trailic conditions may be1accomplished in any suitable manner such, for example, as by means of a home relay 3 and a distant relay 4l. The circuits for controlling these two relays form no part of my present invention and are omitted from the drawing for the salie of simplicity., For present purposes, it is suiiicient to state that home relay 3 is normally energized but is cle-energized when a train occupies the section immediately to the right of point B. The distant relay 4 is also normally energized but is cle-energized when a tra-in occupies. either the iirst or the second section immediately to the right of point B. Vhen relays 3 and 4f are both energized, so that the front contacts of both these relays are closed, currentV from alternator M, which current I will assume to be of 100 cycles per second, is supplied to the trackk rails over Contact 8 opera-ted by cam O3. Un-

der these conditions, the alternating current.

I shall hereinafter term the approach restricting code. In similar manner, when relay 3 is de-energized, a circuit is completed from alternator M tothe track rails through contact 6 operated by cam O1, and the trackway is then supplied with 100 cycle current interrupted at a frequency of 80 cycles per minute, which current I will call the approach code.

A train, indicated diagrammatically at V, is provided with a receiver designated in general by the reference character P. This receiver comprises two magnetizable cores 22 and 22", carried on the train in advance of the forward aXle, and located in inductive relation with the two track rails 1 and 1a, respectively. Core 22 is provided with a winding 23, and core 22a is provided with a similar winding 28, the windings 23 and 23a being connected in series in such manner that the voltages induced therein by alternating currents flowing in opposite directions in the track rails at any instant are additive. rlhe windings 23 and23a are connected, through an amplifier E, with the primary 16 of a transformer Y, the secondary 17 of which is connected directly with a polarized relay D, that is, a relay which is responsive to the polarity of the current supplied thereto. The amplifier Eis preferably of the vacuum tube type which delive rs a unidirectional output current that varies in accordance with variations in the inputcurrent. iVitli-apparatus of the type described, when any code is being supplied to the trackway, each increase in the 100 cycle current in the trackway induces in secondary 1'? of relay Y a current impulse which energizes relay D in one direction, and each decrease of trackway current induces a current ini nilse in secondary 17 which lenergizes relay in the opposite direction. As a result, relay D is operated alternately,iirst in one direction, and then in the other, at the frequency of the code supplied to the trackway. A

The relay D controls apparatus which is selectively responsive to the frequency of operation of the relay. In the present embodiment of my invention, this apparatus is constructed as follows:

Associated with relayA D is a transformer T comprising a primary 19 and a secondary 20. Direct current is supplied to the primary 19 of transformer T from a suitable source of energy such as a battery 28, and this current is periodically reversed at the frequency at which relay D operates. As shown in the drawing, when relay D is energizedin one direction to close contact `18--18a, curient flows from battery 28 through the lower f half of primary 19 in one direction, but when the relay'D is energized in the opposite direction so that Contact 18-18b is closed, current flows frombattery 28 through the upper half of primary 19 in the opposite direction. It follows that when relay D is periodically reversed, the current in primary 19 of the transformer T is periodically reversed at the frequency of the periodic variation in' the trackway current. As a result of this, there is induced in the secondary 2O a low frequency alternating electromotive force which is supplied to a plurality of circuits each designated by the reference character @with a distinguishing exponent, and each comprising a reactor 24 and a condenser 21, by means of which the several circuits are tuned, respectively, to the several code frequencies. For example, circuit C3 is tuned to resonance at the frequency of the clear code or 180 cycles per minute. A relay R3 is connected across a portion of reactor 24: of circuit C3 through a rectifier 71.3. ln similar manner, circuit C2 is tuned to resonance at 12() cycles per minute and relay R2 is ,connected across a portion of reactor 2li of this circuit through a rectifier 7a2. Relay R1 is connected, through rectifier lil and reactor 27,V

directly with secondary 20 of transformer T, and relay R1 is arranged to be energized when relay D is receiving any of the train control code frequencies-` Associated with the relays R are a plurality of stick relays each designated by the reference character S with a distinguishing eX- ponent. The relays R and S may control governing means of any suitable type, which, as here shown, is winding of a magnet valve G arranged when energized to connect a. reservoir 29 with a suitable source of fluid pressure not shown'in the drawing. rl`he reservoir 29 is connected with a relay valve H so that when this reservoir is charged valve H occupies the position shown in the drawing ,and a pneumatic relay 81 is connected by pipe 128 .with a source of fluid pressure so that Contact 32 of this relay is closed. Pipe 128 controls also a brake application valve (not shown) for causing anV application of the brakes when this pipe is connected to atmosphere. When winding 55 of valve G becomes de-energized, the reservoir 29 is connected with atmosphere through a restricted orifice 34 and also through a whistle 33 which gives an audible indication to the engineman. After a brief interval of time, such, for example, as 6 seconds, the pressure in reservoir 29 is so reduced that piston 30 of valve H reverses, thereby venting pipe 128 to atmosphere and applyingY the brakes. At the same time the reversal of valve H connects the pneumaticV relayy 31 with atmosphere, opening contact 32. If magnet valve G is again energized, reservoir 29 is again charged with fluid pressure so'that valve H is restored to its original position and relay 31 closes its contact 32'.

The train is also provided with a manually operable acknowledging switch a located at Sonie convenient place within the reach of the pneumatic llO sceglie engineman, and comprising a normally closed contact 52 and a normally opencontact 7l. When the acknowledging switch is operated, contact 52 is opened, and contact 7l is closed. Furthermore, a reset switch, designated by the reference character r, and comprising a normally closed contact 53 and a normally open contact 106, is provided, andv located outside the cab where it will be inaccessible tothe engineman when the train is in motion.

In explaining the operation of the apparatus as a whole, I will first assume that the clear7 code is being supplied to the trackway so that the trackway current is being interrupted at the frequency of 180 cycles per minute. Relay D therefore operates at the rate of 180 cycles per minute andr alternating current of a corresponding frequency is supplied by secondary 2O of transformer T. Relays It? and R3 are therefore energized, but relay R2 is cle-energized because `the circuit C2 is not resonant at the frequency of the current now supplied to such circuit. With rela-y R3 energized, current flows from battery 28, through wires 37 and 38, front Contact 39 of relay R3, wire 40, lamp -l-l, wire 45, front contact 46 of rela-y R3, and wires 47 and 48, back to battery 28. The lamp 4l is therefore lighted to indicate clear. The circuit just traced is provided with a branch which passes from wire 40, through wires 49 vand 14, winding 35 of relay S3, and wires l5 and 58 back to wire It is therefore plain that winding 35 of relay S3 is connected in parallel with lamp 41, and that relay S3 is energized. Under these conditions a circuit is closed J1 .L l,

roi valve. G, passing irom battery 28, through wires 37 and 89, front contact 50 of relay S3, wire 5l, contact 52 of acknowledging switch a, Contact 53 of the reset switch r, wire 54, winding 55 of magnet vulve G, wire 56, front contact 57 of relay S3, and wires 96 and 48 back to battery 28. Talve G is therefore energized, so that the brakes are not applied.

I will next assume that a change occurs in traflic conditions so that the approach restricting code is supplied to the track-y way. Relay R3'therefore opens and relay R2 picks up, relay R1 remaining in its energized condition. rIhe circuit for lamp 4l is now open at front contacts 39 and 46 of rela-y R3 so that this lamp 1s extinguished. linding of relay S3 is also cle-energized,

vand a circuit is closed for winding 36 of this relay from battery 28, through wires 37 and 38, back Contact 39 of relay R3, wires 59 and 60, front contact 6l of relay R2, wires 62 and 86, front Contact. 87 of relay S3, wire 88, winding 36 of relay S3, wires 85, 7 6, and 66, back contact 46 of relay R1, and wires 47 and 48, back to battery 28. The parts are so constructed that the current supplied to the circuit just traced opposes the effect of the current supplied to winding 35''as described above. The net effect, therefore, is to rapidly neutralize the field of winding 35 and force the relay S3 tofits openposition. Of course,'as soon as contact 87" of relay S3 opens, winding 36 is cle-energized, so the relay does not a-gan pick up, but refmains in its cle-energized condition. The circuit for magnet valve G is opened when front contacts 50 and 57 of relay S3 open, so that the valve starts the reduction of pressure in reservoir 29, and causes whistle to sound.

Since relay R2 is now energized, current flows from battery 28, through wires 37 and 38, back contact 39 of relay R3, wires 59 and 69, front contact 6l of relay R2, vwirer62, lamp 42, wire-63, front contact 64 of relay R2, wires 65 and 66, back Contact 46 of relay R3 and wires 47 and 48 back to battery 28. The lamp 42 is therefore lighted to indicate approach restricting and, lby the change of visual indication, to inform the engineman that upon'the expiration of the time interval required for the blow-down of reservoir 29, an automatic application of the brakes will result. If, however, prior to the reversal of valve I-I the engineman operates the acknowledging switch a, he may forestall an automatic application of the brakes in the following manner:

IVhen contact 7l of switch a is closed, currentflows from battery 28, over wires 37 and 38, back contact 39 of relay R3, wires 59, 67, 68, and 69, Contact 32 of pneumatic relay 3l, wire 70, contact 7l of acknowledging switch a, wires 72, 73 and 74, winding of relay S1, wires 75, 8l, 76, and 66, back contact 46 of relay R3 and wires 47 and 48, back to battery 28. Relay S1 therefore becomes energized and closes a pick-up circuit for relay S2 from battery 28, over wires 37 and 38, back 'contact 39 of relay R3, wires 59, 67, and 77, front contact 78 of relay S1, wire 79, winding 35 of relay S2, wires 80, 8l, 76, and 66, back contact 46 of relay R3, and wires-47 and 48 back to battery 28. Relay S2 therefore picks up. The closingk of front ccntact82 of relay S2 'completes a pick-up circuit for relay S3, from battery 28 over wires 37l and 38, backcoutact 39 of relay R3, wires v59, 67, and 58, front contact 82 of relay S2, wires 83 and 88, winding 36 of relay S3, wires 85, 76, and 66,1back contact 46 of relay R3, and wires 47 and 48 back to battery 28. The relay S3 therefore closes its front contacts. l/Vhen front contact 87 of relay S3 becomes closed, a stick circuit is closed for this relay froml battery 28, over wires 37 and 38, back contact 39 of relay R3, wiresV 59 and 60, front contact 6l of relay R2, wires 62 and 86, front contact 87 of relay S3, wire 88, winding 36 of relay S3, wires 85, 76, and 66, back contact 46 of relay R3, and wires 47 and 48, back to battery 28. The acknowledging switcha may now be restoredto its original position, thereby closing contact 52 and opening contact 71. The circuit for relay S1 is therefore opened and this relay becomes de-energized, and the opening of contact 78 thereon cle-energizes relay S2, but relay S3 maintains its front contacts closed by virtue of the stick circuit just traced and including winding 36 of this relay. `With relay S3 energized and contact 52 of switch a closed, valve G is energized over the circuit previously traced for this valve through front Ycontacts 50 and 57 of relay S3. It follows therefore that when the train is receiving the approach restricting code, and if. the engineman has acknowledged the change in traffic conditions from clear to approach restricting the relay S3 will be held energized and the magnet valve G will be energized to prevent an automatic application of the brakes. Y

Under some conditions, it may happen that when the train is receiving the clear code, relay R3 will become .de-energized for a brief interval under circumstances which should not require a brake application. For example, as the train passes from one track section to the next track section, the supply of train controlling current to the receiver P may be interrupted for a brief time. Of course, thebrakes will not be applied until the expiration of the time required to operate valve H, but as soon as valve G becomes deenergized the whistle 33 will commence to operate, and itis desirable to have this happen only when it is necessary to acklowledge a change in traffic conditions. l/Vith apparatus involving my invention, therefore, I delay the de-energization of valve G, following the opening of relay R3. Thus if relay R3 becomes cle-energized, the circuit for winding 35 of relay Saris opened.` But valve G is not .de-energized until relay `S3 opens, and if relay R2 does not pick up to close the circuit for winding 36, the relay S3 is somewhat slow releasing. It will therefore be'plain that the whistle 33 does not sound until relays P13 and YS3 have opened in succession, and the partsV are proportioned so that the release times of these two relays bridge the ordinary time interval during which relay R3 might bc acci'- dentally Cle-energized.

it should lie-pointed out Vthat after operation of the acknowledging switch a to close Contact 71, the acknowledging switch must be again restored toits original position to close contact after relay Sg has been picked up, in order to permit the magnet valve G to become energized. y i n j i Furthermore, if the acknowledging switch a is not operated before valve H reverses, the operatiouof the acknowledging switch will be ineffective to prevent an automaticV application ofthe brakes. The reason for this is that as soon as valve H reverses, the pneumatic relay 3 1-` operates to open contact-,32,

but the contact 32 is included in the pick-up circuit for relay S1 so that after this contact is open, manipulation of the acknowledging switch a cannot pick up relay S1. If valve H does reverse, the train must be brought to a full stop in order to enable the engineman to operate the reset switch r before valve H can be restored. lVhen switch r is operated, a branch is closed from wire 69, through lwire 105, contact 106 of reset switch r and wire 107 back to wire 73. It will be plain that the closing of contact 106 shunts current around the contact 32 of pneumatic relay 31 and around contact 71 of the acknowledging switch a. When the rest switch r is operated, therefore, the relays S1, S2, and S3 are picked up in order in exactly the same manner as hasalready been explained for the operation of these relays upon manipulation of acknowledging switch a. When relay S3 has become energized, the reset switch 1 may be restored to its original position, thereby allowing relays S1 and S2 to drop. Relay S3 remains energized and magnet valve G becomes lenergized in the manner already described.

I will next assume that upon a further change in trailic conditions, the approach code is supplied to the trackway. Relay R2 opens, but relay R1 is still energized by the current of 80 cycles per'minute which is now supplied to it by transformer T. The deenergiZation of relay R2 interrupts the' circuit for lamp 42 and also breaks the stick circuit for relay S3. The relay S3 therefore becomes cle-energized, and opens the circuit for magnet valve G. The whistle 33 is therefore operated and the blow down of reservoir 29 is initiated so that an automatic application of the brakes will result at the expiration of a time interval unless the engineman acknowledges. `The necessity for this acknowledgment is indicated by the extinguishment of lamp 42 and also by the lighting of lamp 43, which latter lamp is now energized by current which flows from battery 28 over wires 37 and 38, back contact 39 vof relay R3, wires 59 and 60, back contact 61 lof relay R2, wire 91, front contact 92 of relay Rl, wire 93, lamp 43, wire 94, front contact 95 of relay R1, wire 96, back contact 64 of relay R2, wires and 66, back contact 46 of relay RS, and wires 47 and 48 Vback to battery 28. Y

' If the engineman wishes tov forestall an automatic application of the' brakes, he operates the acknowledging switch Va before Vvalve H reverses. Since relay R3 is dc-energized, the closing of the Contact 71 completes the circuit for relay S1 and this relaypicks up, and in turn closes the circuit for winding 35 of relay-S2. Furthermore, the closing of contact 82 of relay S2 picks up relay S.

Acknowledging switch a can now be restored `to its original position. When this happens,

the opening of contact 71 opens the circuit for relay S1 and this relay becomes deenergized. Relay S2, however, is held in its energized position by current which vflows from battery 28 over the circuit already traced for lamp 43 as far as4 wire 93, and thence over wire 97, front contact 98 of relay S2, wire 99, winding 36 of relay S2, wires 81, 76, and 66, back contact 46 of relay R3 and Wires 47 and 48 backto battery 28. Relay S2 is therefore held closed as long as the appreach code is received on board the train. lVith contact 82 of relay S2 closed, relay S3 is also energized and since contact 52 is closed, the magnet valve G is also energized over front contacts 50 and 57 of relay S2, to prevent an automatic application of the brakes. It should be pointed out that should the pneumatic relay 31 open its contact before the engineman actuates the acknowledging switch a, the acknowledgment will be ineffective and he must bring his train to a full stop and operate the reset switch 1" to pick up the stick relays S.

l will next assume that the track circuit i current is cut off to give the most restrictive indication of the system. This indication is designated as caution slow speed. Relay D does not periodically reverse. and relays R2, R2, and R-1 are therefore all de-energized,

i lain-p 43 becomes extinguished, and the stick circuit for relay S2 is opened. Relay S2 therefore becomes cle-energized, and the opening-of front contact 42 thereon de-energizes relay S2. The magnet valve G is thererelay R3, wires 59 and 60, back contact 61 of relay R2, wire 91, back contact 92 of relay R1,

Y wire 100, lamp 44, wire 101, back contact95 of relay R1, wire 96, back contact 64 of relay R2, wires 65 and 66, back contact 46 of relay R3 and wires 47 and 48 back to battery 28.

If the engineman wishes to acknowledge the change in traffic conditions to prevent an automatic application of the brakes, he operates the acknowledgingswitch a. The relays S1, S2, and S3 are therefore picked up in sequence. The engineman then restores the acknowledging switch to its original position. Relay SiL is now maintained in its energized condition by current which flows over the circuit for lamp 44 as far as wire 100, and

thence through wire 102, front contact 103 of relay S1, wires 104 and 74, winding of relay S1, wires 75, 81, 76, and 66, back contact 46 of relay R3 and wires 47 and 48 back to battery 28.L Relay S1 therefore remains 2y front contact 82 of relay S2.

in its energized condition and since contact 78 of this relay is closed, relay S2 isv also picked up, and relay S3 is energized over The magnet valve Grv is therefore energized by current from battery 28 over the circuit including front contacts 57 and 58 of relay S3.

Should traffic conditions'now change in such manner that the approach code is supplied to the trackway, relay R1 becomes energized, but relays R2 and R3 remain cle-energized. rlhe energization of relay R1 completes the circuit for lamp 43 and extingnishes lamp 44 and opens the stick circuit for relay S2. Relay S1 therefore becomes deenergized but the stick circuit for relay S2 is now closed at front contactV 92 of relay R-1 and front contact 98 of relay S2. The deenergization .of relay Sl therefore does not affect. relays S2 or S2 and does not cle-energize magnet valve G. Upon a change in traffic conditions from the caution slow speed to the approach therefore, no acknowledgment is necessary upon the part of the engineman to prevent an automatic application of the brakes.

If, now, traffic conditions change from approach to the approach restricting condition, relay R2 becomes energized. The energization of relay R2 extinguishes lamp 43 and lights lamp 42 and breaks the stick circuit for relay S2 at back contact 61 of relay R2. The stick relay S2 therefore opens, but the stick circuit for relay SB-is now closed at front Contact 61 of relay R2 a-nd front contact 87 of relay S3. The rela-y S3 therefore holds its front contacts closed and magnet' valve G continues to receive current from battery 28 soV that no application of the brakes results from a change is traflic conditions from approach to approach restricting.

Finally, if the clear condition is reestablished, relay R3 becomes energized and relay R2 opens. Lamp 42 is therefore extinguished and lamp 41 is lighted. The stick circuit for relay S3 is also broken so that winding 36 of relay S3 becomes cle-energized. But a circuit is now closed for winding of relayv S3 over front contacts 39 and 46 of relay R3 as de# scribed hereinbefore. lt will be remembered, however, that windings 35 and 36 are connected in opposition, so that when winding 35 becomes energized, the field of winding 36 is first neutralized to cle-energize the relay, which then again picks up under the influencel of the current in winding 35. During a short interval of time, however, `relay R3 is energized, and relay S3 is open, and during this interval, current flows from battery 28, through wires 37 and 38, front contact 39 of relay R3, wires 40 and 49, back contact 50 of relay S3, wire 51, contact 52 of switch a, contact 53 of switch 7, wire 54, winding 55 of Valve Gr, wire 56, back-contact 57 ofrelay S3, wires 58 and 45, fro-nt contact 46 of'relay R2, and wires 47 and 48 back to battery 28. Valve' G is therefore held energizedwhile relay S3 is open, and after relayS3 again pic-ks y said relay is open, and governing means on.

CII

up, valvey G is energized over the circuit first traced for this valve including front contacts and 57 of relay S3. It follows that no application of the brakes results from a change from approach restricting to clear traffic conditions.

In conclusion, it should be pointed out that the apparatus is arranged in such manner that upon any change in traffic conditions from a less restrictive to a more restrictive indication, an automatic application of the brakes will result unless the engineman operates the acknowledging switch a during the time interval required for the blow down of reservoir 29. Upon any change from a more restrictive to a less restrictive indication however, the magnet valve G does not become cle-energized and no acknowledgment by the engineman is necessary.

Furthermore, the apparatus is arranged to sound the whistle 33 to warn the engineman of a change in traffic conditions which necessitates his acknowledgement, but the whistle does not operate if relay R3 is cle-energized for a brief interval of time while the train is proceeding under clear conditions. f

Although I' have herein shown and described only one form of railway traffic con# trolling apparatus embodying my invention, it is understood that various changes and modifications may be made therein wit-hin the scope of the appended claims without depart ing from the spirit and scope of my invention.

I-Iaving thus described my invention, what I claim is: v

1. Railway traffic controlling apparatus comprising a train carried` differential relay having two opposed windings, means located partly in the trackway for energizing one winding ofsaid relay under certain traffic conditions, means operating upon a change to certain other trafiic conditions to energize the second winding -to open said relay, means under the control of the engineman and ef'- fective under said other traffic conditions to energize said second winding to close the re': lay, a signal arranged to be `operated when the train set into operation at the expiration of a fixed interval of time after said relay is opened.

2. Railway traffic controlling apparatus comprising a first and a second train carried relays, means for selectively energizing said relays in accordance with trafiic conditions, a third relay having two opposed windings, a circuit for one winding of said third relay including a front contact of said first relay, a pick-up circuit for the other'winding of said third relay under the control of the yengineman and including a back contact of said first relay, a stick circuit for said other winding. of the third relay including a front contact of said third relay and a front contact of said second relay as well as a back contact of said first relay, a valve controlled by said third relay, and train governing means controlled by said valve. Y

3. Railway traffic controlling apparatus comprising a first and a second train carried relays, means for selectively energizing said relays in accordance with traffic conditions, a third relay having two opposed` windings, a circuit for one winding of said third relay including a front contact of said first relay, a pick-up circuit for the other winding of said third relay under the control of the engineman and including aback contact of said first relay, a stick circuit for said other winding of the third relay including a front contact of said third relay and a front contact of said second relay as well as a back contact of said first relay, a magnet, a first circuit for said magnet including a front contact of said third relay, a second circuit for said magnet including a back contact of said third relay and a front contact of said first relay and train governing means controlled by said magnet.

4. Railway trafiic controlling appara-tus coinprisinga first'and a second train carried relays, means for selectively energizing said relays in accordance with trafiic conditions, a third relay having two opposed windings, a circuit foi-'one winding of said third relay including a front contact of said first relay, a pick-up circuit for the other winding of said third relay under the control of the engineman and including a back contact of said first relay, a stick circuit for said other winding ofthe third relay including a front contact of saidthird relay and a front contact of said second relay as well as a back contact of said first relay, a magnet, a first circuit for said magnet including a front contact of said third relay, a second circuit for said magnet including a back contact of said third relay and a front contact of said first relay, a sig# nal arranged to operate when said magnet is de-energized, andmeansy effective upon the expiration of a time interval after said magnet becomes de-Venergized to apply the brakes.

Intestimony whereof I affix my signature.

' RONALD A. MCCANN. 

